...the "cat room" in Dilbert's Ultimate Home (DUH)
"Statistics show that there are approximately 90 gazillion cats living in houses. If your house is one of them, you probably have the cat's litter box in a bathroom or someplace else equally embarrassing and annoying. Dilbert anticipated a future pet cat and built a room to keep all the ugly pet-related stuff out of sight. It's near the garbage room, for those daily kitty litter cleaning duties. The door has a pet door at the bottom. Inside, the room has water for drinking and for cleaning the tile floors. All the food and pet supplies are on shelves. The cat box is raised to waist level so it's easier to clean. The cat has its own little stairs to get up to it.
A heated cat bed rounds out the space, so your cat can stay in there indefinitely if you need to entertain guests who are allergic."
http://www.dilbert.com/comics/dilbert/duh/tour.html